Present day communications technology is directed more and more to the use of optical fibers for signal transmission. Optical fibers have the undisputed advantage over wire transmission media of far greater signal bandwidth transmission capability, but the physical disadvantage of being far more fragile than metallic wire. Thus, the handling and routing of optical fibers, whether singly or in cables not only demands extreme care in handling, but, also, extra measures of protection for the fibers. In routing either cables or single fibers, it is imperative, for reliable signal transmission, that sharp bends in the fibers be avoided. Inasmuch as the laws of optics apply to such transmission, a too sharp bend in the fiber can and does result in signal loss by virtue of at least some of the transmitted light leaking out of the fiber at the bend. A too sharp, i.e., small radius, bend can also cause at least some further signal degradation if the bend introduces microcracks in the fiber, which reduce or impair the un-interrupted guiding of the optical signals. Most optical fiber being made today is capable of resisting formation of such microcracks, but when the fiber is subjected to recurring external forces, the tendency toward cracking increases.
In most environments where optical fiber cables terminate in, for example, an office building or in other user premises, the individual fibers are separated out of the cable and directed, by means of connectors and patch panels, to the particular user or to the particular signal receiving and/or transmitting equipment. Thus, in a typical patch panel arrangement, the fibers are separated on one side (or face) of the multi-apertured panel, and connectors are affixed to the ends of the fibers. The connectors typically are inserted into couplers mounted in the panel into which connectors or individual fibers are also inserted from the rear side of the panel. Typical of such arrangements are those shown in U.S. Pat. Nos. 5,238,428 of Arnett, which is for electrical connection and 5,274,729 of King, et al., which is for optical fiber connection. It can be appreciated that the cable leading up to the front of the panel affords protection from sharp bends for the individual fibers, and only the small lengths of unprotected fibers that are necessary to reach the different couplers are exposed. Thus, there is little likelihood that the fibers may be kinked or bent too sharply. 0n the other hand, however, the individual fibers leading away from (or up to) the rear of the panel are essentially unprotected. If these latter fibers are allowed to hang loosely from the rear of the panel, they are in danger of becoming bent, twisted, or kinked, with consequent degradation of transmission, especially when an installer, for example, is working at the rear of the panel, making connections and disconnections.
In U.S. Pat. No. 4,372,511 of Knowles, there is shown an optical fiber strain relief assembly for routing fiber cables from a back plane, which may be the rear surface of, for example, a patch panel, to individual equipment modules. In that assembly, a cable bundle is supported in a straight trough from which individual cables are routed into separate curved troughs having approximately a one inch radius of curvature and arrayed along the straight trough. The individual cables are supported in the curved troughs, which prevent their being bent too sharply, and hence, microcracks and signal transmission degradation and loss are avoided. The assembly is mounted to the backplane by means of individual screws for each of the curved troughs of the assembly, and the cables themselves are retained within their respective troughs by means of straps. Such an arrangement affords protection to the cables by containing them within the troughs and prevents their being bent too sharply. However, the arrangement must be assembled and mounted, and the patent is silent as to the treatment of individual connectorized fibers, for example.